<?php
/**
 * Enqueues the Agentyme chatbot widget on the frontend.
 */

defined( 'ABSPATH' ) || exit;

class Agentyme_Frontend {

	const WIDGET_HANDLE = 'agentyme-widget';
	const RUNTIME_HANDLE = 'agentyme-runtime';

	public function __construct() {
		add_action( 'wp_enqueue_scripts', [ $this, 'enqueue_chatbot' ] );
		add_filter( 'script_loader_tag', [ $this, 'add_widget_script_attributes' ], 10, 3 );
	}

	/**
	 * Enqueues the chatbot widget if a valid API key is configured.
	 */
	public function enqueue_chatbot(): void {
		// Don't enqueue in admin, REST API, or if the key isn't validated.
		if ( is_admin() || wp_is_json_request() ) {
			return;
		}

		$api_key   = get_option( Agentyme_Admin::OPTION_API_KEY, '' );
		$key_valid = (bool) get_option( Agentyme_Admin::OPTION_KEY_VALID, false );

		if ( empty( $api_key ) || ! $key_valid ) {
			return;
		}

		wp_register_script(
			self::RUNTIME_HANDLE,
			false,
			[],
			AGENTYME_VERSION,
			true
		);

		wp_add_inline_script(
			self::RUNTIME_HANDLE,
			$this->get_inline_widget_config( $api_key )
		);

		wp_register_script(
			self::WIDGET_HANDLE,
			Agentyme_API::PLATFORM_URL . '/widget.js',
			[ self::RUNTIME_HANDLE ],
			AGENTYME_VERSION,
			true
		);

		wp_enqueue_script( self::WIDGET_HANDLE );
	}

	/**
	 * Adds the API key data attribute to the widget script tag.
	 *
	 * @param string $tag    The script HTML tag.
	 * @param string $handle The script handle.
	 * @param string $src    The script source URL.
	 *
	 * @return string
	 */
	public function add_widget_script_attributes( string $tag, string $handle, string $src ): string {
		if ( self::WIDGET_HANDLE !== $handle ) {
			return $tag;
		}

		$api_key = get_option( Agentyme_Admin::OPTION_API_KEY, '' );

		if ( empty( $api_key ) ) {
			return $tag;
		}

		return wp_get_script_tag(
			[
				'id'           => $handle . '-js',
				'src'          => $src,
				'data-api-key' => $api_key,
			]
		);
	}

	/**
	 * Returns inline configuration and browser compatibility code for the widget.
	 *
	 * @param string $api_key Validated API key.
	 */
	private function get_inline_widget_config( string $api_key ): string {
		$config = wp_json_encode(
			[
				'apiKey' => $api_key,
			]
		);

		return 'window.agentymeConfig = ' . $config . ';' . "\n" . <<<'JS'
( function() {
	if ( window.crypto && typeof window.crypto.randomUUID === 'function' ) {
		return;
	}

	var cryptoObject = window.crypto || {};

	if ( typeof cryptoObject.getRandomValues !== 'function' ) {
		cryptoObject.getRandomValues = function( values ) {
			for ( var index = 0; index < values.length; index++ ) {
				values[ index ] = Math.floor( Math.random() * 256 );
			}
			return values;
		};
	}

	var randomUUID = function() {
		return ( [ 1e7 ] + -1e3 + -4e3 + -8e3 + -1e11 ).replace( /[018]/g, function( character ) {
			return ( character ^ ( cryptoObject.getRandomValues( new Uint8Array( 1 ) )[ 0 ] & ( 15 >> ( character / 4 ) ) ) ).toString( 16 );
		} );
	};

	try {
		Object.defineProperty( cryptoObject, 'randomUUID', {
			configurable: true,
			value: randomUUID
		} );
	} catch ( error ) {
		cryptoObject.randomUUID = randomUUID;
	}

	if ( ! window.crypto ) {
		window.crypto = cryptoObject;
	}
}() );
JS;
	}
}